Testing

Treat a test as an experiment. Add or run one when a concrete unknown remains, a credible wrong behavior is possible, and the result would change the implementation or release decision.

1. State the required behavior and the wrong behavior still left open.
2. Choose the smallest boundary with an independent oracle.
3. Exercise the case, boundary, failure, or recovery that can distinguish them.
4. Read every result and report what remains untested.

Read the detailed guide for test sensitivity, doubles, flaky signals, properties, or suite design. A justified "no new test" is a valid result when existing evidence is sufficient.